There are currently \(\sim 300\)  SNRs cataloged in our Galaxy [1]},
although radio surface brightness studies predict that
only half of SNRs have been identified [2]}.
Recent X-ray observations with good spatial resolution and large effective area allow us to detect many SNR samples
in nearby galaxies as well, such as Magellanic Clouds[3]}, M31[4]}, and M33[5]}.
